1. Field of the Invention
The present invention relates to a snowmobile having a steerable ski supported on a front portion of a vehicle body and an endless track device supported on a rear portion of the vehicle body.
2. Description of Background Art
An endless track device for a snowmobile is disclosed in U.S. Pat. No. 4,093,033. This endless track device includes a drive wheel, a swing arm pivotably supported to a vehicle body, a side rail supported to a rear end of the swing arm and extending in a longitudinal direction of the vehicle body, idlers supported to a front portion and a rear portion of the side rail, and a track belt wrapped around the idlers and the drive wheel. The side rail is formed with a slider extending in the longitudinal direction for slidably guiding the track belt. The front end of the slider extends to a position in the vicinity of the drive wheel.
Further, a rear cushion device consisting of a damper and a cushion spring is provided between the swing arm and the side rail.
When an impact load is applied from a snow surface to the side rail of the endless track device during operation of the snowmobile, the swing arm is swung upwardly. At this time, the front end of the side rail moved upwardly together with the swing arm is gradually separated from a portion of the track belt between the drive wheel and the front idler. Eventually, the swing arm cannot slidably guide the track belt.